MCQ quick facts

Question 1

Starling equation values for kidneys

Answer 1

• Lp = Constant
• S = 0.8m2
• P_Gc = ~60mmHg
• P_BC = ~15mmHg
• σ = 1
• π_Gc = 29mmHg
• π_BC = Negligible in health

Question 2

Malignant hyperthermia incidence

Pharmacogenetics

Answer 2

1:5,000 - 1:50,000

Question 3

Atypical plasma cholinesterase/pseudocholinesterase

Congenital/acquired/both/neither?

Pharmacogenetics

Answer 3

Fails to metabolise suxamethonium and causes “sux apnoea”
○ Congenital - autosomal recessive
○ Acquired - due to loss of plasma cholinesterase. Can occur in pregnancy, organ failure (hepatic, renal, cardiac), malnutrition, hyperthyroidism, burns, malignancy, drugs (OCP, ketamine, lignocaine and ester Las, metoclopramide, lithium)
○ Note: acquired disease will have normal dibucaine no but just decreased quantity of enzyme

Question 4

G6PD deficiency

Pharmacogenetics

Answer 4

Mutation of glucose 6-phosphate dehydrogenase which produces acute haemolysis in response to oxidative stress due to dapsone, methylene blue, fluoroquinolones, antimalarialas and rasburicase

Question 5

Normal cardiac output and cardiac index values

Answer 5

CO = 5L/min; CI = 2.5-4L/min

Question 6

LaPlace’s Law (cardiac)

Answer 6

sigma = Pr/2h

where sigma = myocardial wall stress
P = transmural pressure
r = radius
h = ventricular wall thickness